This invention relates generally to a shading system. More specifically the invention relates to a liquid crystal (L.C.) panel having zones which are selectively operable by an electronic control to various states of opaqueness to produce desired shading patterns.
Reference is made to application Ser. No. 527,435 filed Aug. 26, 1983, commonly assigned, which relates to a liquid crystal panel shade. The disclosure of that application relates to a liquid crystal sun visor for providing shading to the eyes of an occupant of an automobile.
The prior art referred to in that patent application identifies the following general categories of shading systems:
(1) Prismatic systems in which glare is reduced by prismatic elements having different indicies of refraction including liquid-containing prisms;
(2) Shutter systems in which mechanical shutters are selectively operable to control shading;
(3) Photochromic systems in which photochromic material responds to changes in incident light so as to increasingly darken in response to a higher intensity of light and to become less dark in response to a lower intensity of light;
(4) Tinted liquid systems in which tinting is controlled by tinted liquid pumped between window glass panes;
(5) Polarizer systems containing light polarizers.
There have also been previous attempts to apply liquid crystals to window panes.
The following prior art patents relate to these various categories: U.S. Pat. Nos. 3,324,469; 2,423,322; 3,400,972; 3,368,862; 3,695,681; 2,423,322; 2,562,895; 3,961,181; 3,986,022 and 4,268,126.
The invention of application Ser. No. 527,435 provides for control of the area of opaqueness of a liquid crystal panel sun visor and hence a control of a shaded area within the interior of the automobile. In the disclosed embodiment of a liquid crystal panel sun visor, the extent of the opaque zone is adjusted so as to provide shading of an occupant's eyes when seated in the vehicle.
The present invention is directed to a novel and unique liquid crystal panel shading system. The invention is disclosed in an illustrative form as a vehicle sunroof panel although it will be appreciated that principles of the invention may be applied to other applications. In the disclosed application of the invention in a sunroof panel, the liquid crystal is divided into a multitude of individual zones which are under the control of an electronic control system. The invention includes a control for selectively controlling the individual zones to desired degrees of opaqueness so as to provide a desired shading pattern within the vehicle.
One of the advantages of the invention is that substantial amounts of light may be allowed to pass through certain portions of the panel while other portions of the panel are controlled to block or at least attenuate the light transmission into the interior of the vehicle. Thus for example, it is possible for an individual occupant of the vehicle, say the driver, to sit in a shaded area while full light is allowed to pass through the panel onto other areas. Moreover, in the disclosed embodiment the shading pattern may be considered as analogous to an umbrella with a control handle provided for use by an occupant corresponding to the handle of an umbrella. The control handle is positioned (i.e. aimed) by the individual to position the shaded area of the panel in the same manner that an individual would use an umbrella's handle to position the umbrella, but without there being any mechanical connection. Moreover the disclosed embodiment has a provision for controlling the size of the opaque area and also for controlling the degree of opaqueness. Thus it is possible to expand and contract the size of the shade, to selectively position it, and to set its degree of opaqueness.
The present invention also includes another aspect of an automatic control for automatic control of the shade both with respect to opaqueness and position whereby once an occupant has set the desired area to be shaded and the intensity of shading, the automatic control is effective to maintain that area and degree of shading with respect to any changes in the relative position of the vehicle and the sun. In this way the system automatically tracks the sun as it moves across the sky and it also automatically adjusts for changes in the vehicle's direction of travel.
With the present invention in application to a vehicle sunroof panel, new opportunities are available to automobile stylists and designers. For the vehicle occupant it is possible to have desired levels of interior illumination yet to provide shading from direct sunlight at desired locations and in particular degrees. Therefore the invention provides a capability heretofore not available and which is susceptible to numerous possible implimentations.
The foregoing features, advantages, and benefits of the invention, along with additional ones, will be seen in the ensuing description and claims which should be considered in conjunction with the accompanying drawings. The drawings disclose a preferred embodiment of the invention according to the best mode contemplated at the present time in carrying out the invention.